#include<stdio.h>

int flag=0;

int Sum(int s,int e)
{
    int sum=0;
    int i=0;
    for(;i<e;++i)
    {
        sum+=i;
    }
    return sum*flag;
}

int Add(int x,int y)
{
    return x+y;
}

int Div(int x,int y)
{
    if(y==0) return -1;
    int z=x/y;
    return z;
}

int main()
{
    printf("process is running\n");

    int start=1;
    int end=100;
    int result=Sum(start,end);
    printf("process is done,result: %d\n",result);

    int a=Div(10,0);
    printf("process is done,div result:%d\n",a);

    int b=Add(10,20);
    printf("process is done, add result:%d\n",b);

    return 0;
}
